"Bitcoin now seems like a charging train with no brakes," said Shane Chanel, an adviser at investment services firm ASR Wealth Advisers. "There is an unfathomable amount of new participants piling into the cryptocurrency market."

Bitcoin is the most popular cryptocurrency -- a kind of virtual "coin" that is "mined" by computers using complex algorithms.

During its epic rally this year, bitcoin has suffered a series of steep drops, reminding of its extreme volatility. After breaking above $11,000 last week, it abruptly plunged by more than $2,000 before resuming its climb.